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Chemistry · Glossary

What is Period and group?

Also known as: period · group

Definition 20.2 School Chemistry — Grades 1 to 12 · Chapter 20 — The Periodic Table: A First Look

A row of the periodic table is a period; there are seven. A column is a group; there are eighteen, numbered 1 to 18 from left to right. The two rows printed below the table belong in periods 6 and 7; they are set apart only to keep the table narrow.

The periodic table. Each box gives the atomic number and the symbol. Colours: metals, metalloids (elements between metals and non-metals) and non-metals, in the usual classification.
The periodic table. Each box gives the atomic number and the symbol. Colours: metals, metalloids (elements between metals and non-metals) and non-metals, in the usual classification.
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